New research suggests protein supplementation improves gains in muscular strength and size.

With research suggesting that over 25% of regular gym-goers use it and annual U.S. sales exceeding $6B, dairy-based protein is the single most used product in the sports supplement world. Like most products in the sports supplement industry, it is best you take the marketing claims with a mountain of salt (Himalayan Pink of course), but a recently published study provides strong evidence that you may be leaving some strength and hypertrophy gains on the table if you are following your workouts with only whole food protein sources.

The history of protein supplementation dates back further than the most stinky of cheeses. Whey, the most popular dairy-based protein supplement, was identified over 7,000 years ago, but throughout most of history was simply known as the byproduct of cheese making that soured and was ultimately tossed. Its health benefits did become widely recognized by the ancient Romans, as Hippocrates (often known as the father of modern medicine) often prescribed it to improve health, and it maintained a following amongst the health conscious in Europe for centuries. Then in the 1930s, American pharmacist Eugene Schiff developed a method of processing the whey from milk so that it could be used easily for human consumption. After patenting the process, he began selling it to drug stores and the military as a more condensed form of additional dietary protein than the conventional powdered milk. With Charles Atlas and Steve Reeves posters becoming commonplace on the walls of American teenage boys, jars of powdered whey protein became the first bodybuilding supplement.

While today you can browse online retailers and find countless protein varieties, everything from chia to potato protein, it is the dairy-derived whey and casein that are the most popular and most researched. When it comes to promoting gains in strength and muscular size, whey and casein have several scientifically-validated benefits. Whether concentrate or isolate (or now, the less popular hydrolysate), the difference simply being the type and degree of processing of the unfiltered cheese byproduct, whey contains very little fat and cholesterol when compared to most other sources of complete (containing adequate proportions of the nine essential amino acids) protein, is fast-digesting, and contains high levels of branched-chain amino acids, so it promotes quick increases in protein synthesis. It has the highest bioavailability (the measurement of the percentage of how much of a particular substance the human body can process and use) of any known protein source and it is economical and convenient. The less popular casein, actually the most abundant form of protein in cow’s milk, has its own separate set of benefits. Due to its slower absorption in the gut, casein is most commonly used to maintain protein synthesis when your body might otherwise be in a catabolic state, such as during sleep, or prior to an extended fast, when your body may otherwise break down lean tissue to support metabolic processes. Due to its superior ability to sustain nitrogen retention, casein has also shown to be superior to other protein sources when one is on a calorie-restricted diet with the aim of losing weight. Back-of-the-napkin nutritional analysis: if it is difficult to meet your protein needs with whole food sources alone, the benefits of dairy-derived protein supplements are hard to beat.

Despite the well-understood benefits and biological mechanisms of action, the empirical research regarding the overall benefits of dairy-derived protein supplementation on muscular and strength gains has still been mixed. The British Journal of Sports Medicine recently published the most extensive review to date of the current literature regarding the influence of whey and casein protein supplementation on resistance training-induced gains in muscle mass and strength, which may ultimately put the debate to protein-synthesizing rest. Analyzing data from 49 separate studies, which included nearly 1,900 total participants, researchers concluded that whey and casein protein supplementation significantly enhanced muscular hypertrophy and strength in healthy adults when used in conjunction with regular resistance training; an average of 27% gains were seen when compared to controls who did not supplement their normal diet. Of comparable importance, the data did not seem to suggest that protein supplementation beyond the current recommendations of 1.6-1.8 total grams of protein per kilogram of body weight further enhanced gains, nor did consuming it shortly following a workout in the so-called “anabolic window.” In short, that shaker bottle with a scoop of your favorite protein is a vital element in your body composition improvement plan, but more protein isn’t necessarily better and it isn’t that big of a deal if you forget to put it in your gym bag and have to wait a while before guzzling it down.

Similar to a lot of the more recent nutritional science research, the numbers suggest that the devil isn’t necessarily in the details. Protein supplementation is important in maximizing muscular and strength progression, but as long as you are hitting intake thresholds, there is no real reason to stress over the minutiae of total macronutrient content or timing. Let your taste buds and overall schedule determine how much and when you should be shaking it up.

Dr. Damian Rodriguez is the health and exercise scientist for doTERRA International, LLC. He holds a doctorate in health science, a master’s degree in exercise physiology, and countless professional certifications. He has spent most of his life researching nutrition, exercise, and the lifestyle behaviors associated with optimal health. Along with his passion for health, as someone who lives with Asperger’s Syndrome, he is also involved in bringing awareness to autism spectrum disorders. There are varying opinions about many health and fitness topics. His opinions are his own and not necessarily that of doTERRA International, LLC. Consult your healthcare provider before making any changes to diet and exercise.